Usefulness of Citric Cough Test for Screening of Silent Aspiration in Subacute Stroke Patients: A Prospective Study

Cough reflex attenuation and swallowing dysfunction in sub‐acute post‐stroke patients: prevalence, risk factors, and clinical outcome

“…However, few studies have used this methodology to assess the cough reflex in PSP . We considered a failed CRT response to be when five coughs (C5) were not provoked with the highest citric acid concentration, criteria also used by other authors . This event was detected in 14% (2) of all HV, similar to the rates previously reported (8–53%) and in 5.8% of PSP, lower than the incidence published in the literature when CRT was assessed by citric acid cough challenge (17.6–46.9%) at the acute post‐stroke stage.…”

“…This protocol measures cough reflex sensitivity to citric acid and facilitates universal interpretation and data comparison. However, few studies have used this methodology to assess the cough reflex in PSP . We considered a failed CRT response to be when five coughs (C5) were not provoked with the highest citric acid concentration, criteria also used by other authors .…”

“…A limiting factor could be that we used a clinical test (V‐VST) and not an instrumental test to assess swallowing function, so we could not specifically contrast the relationship between a failed cough reflex and the presence of silent aspirations. Varying results have been reported when evaluating cough function as a predictor of silent aspirations, some studies reporting high sensitivity and specificity and some reporting contrary results . These differences could be explained by variations in methodology (voluntary cough versus reflex cough and different exploration methods), populations, and the mechanisms of cough elicitation (cough caused by aspirations occurs by stimulation of laryngeal mechanoreceptors and cough caused by inhalation of irritant agents, by the stimulation of C‐fibers) .…”

“…Cough is also a complex response that depends on sensory processes that begin in the airways, involve complex brainstem and higher brain control systems (cortical and subcortical) and are not fully understood. The incidence of post‐stroke cough dysfunction has been found to be from 17.6% to 46.9% . However, little is known about the clinical and neurological characteristics of stroke associated with impaired cough response and their impact on clinical outcome.…”

“…The incidence of post-stroke cough dysfunction has been found to be from 17.6% to 46.9%. 10,[15][16][17][18] However, little is known about the clinical and neurological characteristics of stroke associated with impaired cough response and their impact on clinical outcome.…”